Vuilleumier refrigerator hot cylinder burner head

ABSTRACT

Vuilleumier refrigerator has its hot cylinder heated by a burner head. The burner head includes a heat transfer surface of concave configuration and rough surface in thermally conductive relationship to the hot volume.

United States Patent Leo July 1, 1975 [54] VUILLEUMIER REFRIGERATOR HOT2,484,392 10/1949 VanHeeckeren 62/6 CYLINDER BURNER HEAD $5 3, 27 8/1970[75] Inventor; Bruno S. Leo, Santa Momca, Cahf. 3 742 719 7 973Assignee: Hughes Aircraft p y, Culver 3,774,405 ll/l973 Leo 62/6 1 y CaIf Primary Examiner-Wtll1am J. Wye

[ Filfidi 1974 Attorney, Agent, or Firm-Allen A. Dicke. Jr.; W. H.

21 Appl. No.: 449,182 MacAlllsmr 57 ABSTRA T [52] US. Cl 62/6; 62/87 51Int. Cl. F25]; 9/00 vmlleumler refrlgerawr has Its hot cylmder heated y581 Field of Search 62/6 3 burner head- The burner head includes a heattransfer surface of concave configuration and rough sur- 5 Refu-encesCited face in thermally conductive relationship to the hot UNITED STATESPATENTS 1.275,507 8/1918 Vuilleumier 62/6 3 C aims, 1 Drawing FigureVUILLEUMIER REFRIGERATOR HOT CYLINDER BURNER HEAD BACKGROUND Thisinvention is directed to a cryogenic refrigerator operating on theVuilleumier cycle and particularly to the heater structure for supplyingthe refrigerator power.

Vuilleumier cycle refrigerators are known. The original disclosure wasin U.S. Pat. No. 1,275,507 by Rudolph Vuilleumier. That heat cycle hasbeen developed and modernized into an efficient miniaturized cryogenicrefrigerator. An example of that is shown in K. W. Cowans U.S. Pat. RE.No. 27,338. Particular mechanical structure of such a refrigerator isfound in G. P. Lagodmos U.S. Pat. No. 3,742,719. Prior cryogenicrefrigerators using this cycle have employed heating by using anelectric resistance heater wrapped around the hot end of the hotcylinder. This is a convenient way of producing the necessary hightemperatures, but, in some installations and under some circumstances,electric heating is less satisfactory than a fuel combustion situation.The present disclosure is directed to an efficient way of providing heatto the hot cylinder by fuel combustion.

SUMMARY In order to aid in the understanding of this invention, it canbe stated in essentially summary form that it is directed to aVuilleumier refrigerator hot cylinder burner head, and particularlystructure which results in efficient heat transfer from fuel combustionproducts into the hot end of the hot cylinder. lt includes a shapedcombustion surface of rough character for efficient combustion and heattransfer.

It is thus an object of this invention to provide a hot cylinder burnerhead structure for a Vuilleumier refrigerator which permits thecombustion of gas and similar fuels for hot cylinder heating. It is afurther object to provide a Vuilleumier refrigerator having a heatingsystem which eliminates the need for electric heating. It is a furtherobject to provide a hot cylinder heating structure which provides forefficient combustion and efficient heat transfer. It is a further objectto provide a Vuilleumier hot cylinder heater which is economical ofconstruction, and fuel consumption trouble free in use, and reliable inoperation.

Other objects and advantages of this invention will become apparent froma study of the following portion of the specification, the claims andthe attached drawmgs.

BRIEF DESCRIPTION OF THE DRAWINGS The single FIGURE of the drawings issubstantially a central longitudinal section through a Vuilleumierrefrigerator having a hot cylinder burner head in accordance with thisinvention.

DESCRIPTION The Vuilleumier refrigerator, including the burner head ofthis invention is generally indicated at 10. Vuilleumier refrigerator10, has a hot cylinder 12, which contains hot displacer 14. Heat isadded to head 16 of the hot cylinder to supply input power to therefrigerator. The refrigerator also has a cold cylinder 18 in which islocated cold displacer 20. The cold end of cold cylinder 18 carriesdevice 22 for which cryogenic renecessary insulation. 5

frigeration is suppliedby the refrigerator. Housing 28 has an insulatingdevice, such as a Dewar to provide the Crankcase 24 contains crank '26.Connecting rods appropriately connect to both of the disp-Iacers tocontrol them in proper cyclic relationship to operate the refrigeratoron the Vuilleumier cycle. It should be noted that the warm end of boththe hot and cold cylinders, which includes crankcase 24, is aboveambient to permit heat rejection to atmosphere. Thus, the warm ends ofboth regenerators 30 and 32, are connected with finned tubing, shown onthe drawing, or are otherwise arranged so that the refrigerant gas atthe warm ends of these generators can reject heat to the ambient. Therefrigerator thus described is the one shown in K. W. Cowans U.S. Pat.RE. No. 27,338. Housing 34 embraces much of the refrigerator structureand contains fan 36 for moving air from left to right through housing 34for cooling the warm section of the refrigerator.

Gas nozzle 44 is provided with a combustible gas under pressure. The gasis directed into the venture throat 46 to induce air into primary airinlet 48. The gas and primary air mixture passes into gas chamber 50 andpasses through annular nozzle throat 52. Nozzle throat 52 is formedbetween cone 42 and collar 54. Collar 54 is adjustably mounted, as bybeing mounted on screwthreads as shown, so that the gap can be adjusted.On its way to the annular nozzle throat 52, the combustible gas passesthrough orifices 56. Orifices 56 have a sufficiently high velocitytherethrough that the flame front cannot pass back into gas chamber 50.Thus, collar 54 basically holds the flame against the outside of cone42. From the bottom of the cone, the flame and now principally hot gasof the products of combustion spread outward on the heat transfersurface 40 which is part of a sphere. The surface finish of heattransfer surface 40 is sufficiently rough, about 1000 microinchesroughness height, to enhance heat transfer and maintain high transferrates. Heat transfer surface 40 is formed on head 38, and head 38 may bean integral head on the hot cylinder. On the other hand, it may be aseparate device which is attached by any convenient means, such as ascrewthread; however, when there is a separate head it must lie in closethermal relationship to the hot cylinder. The resultant products ofcombustion preheat the incoming gas mixture and secondary air and thenexhaust from gas openings 58 and 60 into the air stream passing out ofrefrigerator 10.

Secondary air is induced through secondary air inlet 62 and isdischarged to the burning gas area through the nozzle embracing collar54. Combustion takes place along surface 40 with the secondary airdirectly delivered. Throat 52 acts as the flame stop with orifices 56providing secondary flame stop protection.

This invention having been described in its preferred embodiment, it isclear that it is susceptible to numerous modifications and embodimentswithin the ability of those skilled in the art and without the exerciseof the faculty. Accordingly, the scope of this invention is defined bythe scope of the following claims.

I claim:

1. A Vuilleumier-type refrigerator comprising:

a hot cylinder having a head, a concave curved thermal heat transfersurface on said head, a solid cone extending from said curved heattransfer surface;

a fluid fuel burner formed around said cone so that combustion flameimpinges along said cone and onto said curved heat transfer surface sothat products of the combustion pass along said heat transfer surface sothat heat is provided for the hot cylinder of the Vuilleumierrefrigerator.

2. The refrigerator of claim 1 wherein a collar is positioned aroundsaid cone to form said noz zle as an annu- V combustion to said hotcylinder heat.

1. A Vuilleumier-type refrigerator comprising: a hot cylinder having ahead, a concave curved thermal heat transfer surface on said head, asolid cone extending from said curved heat transfer surface; a fluidfuel burner formed around said cone so that combustion flame impingesalong said cone and onto said curved heat transfer surface so thatproducts of the combustion pass along said heat transfer surface so thatheat is provided for the hot cylinder of the Vuilleumier refrigerator.2. The refrigerator of claim 1 wherein a collar is positioned aroundsaid cone to form said nozzle as an annular nozzle.
 3. The refrigeratorof claim 1 wherein said curved heat transfer surface is rough to enhanceheat transfer and maintain high heat transfer rates from products ofcombustion to said hot cylinder heat.